Rotary mechanical face seals with metal bellows are used in high temperature applications. They are also used in systems handling cryogenics, heat transfer fluids, corrosive and abrasive chemicals, refinery products, and in chemicals where many other types of seals would be destroyed. Such bellows are formed of a series of annular metal discs or diaphragms welded together to form an axially compressible bellows. The capacity of the bellows is limited by the strength of the weld joints.
U.S. Pat. No. 3,090,403 to Kroekel exemplifies one form of bellows in the prior art. This patent discloses the use of laminated annular diaphragms, welded together at their inner and outer circumferences. Stress is divided between the separate laminae, to reduce the stress borne by the individual diaphragms.